The common event attribution and assessment (CEAA) project of the WCRP Explaining and Predicting Earth System Change (EPESC) Lighthouse Activity seeks to identify extreme weather and climate events for coordinated study. The project will identify selected extreme events and provide information on the time period covered by the event, the region where the event occurred, and extremes metrics to characterise the event. The global extreme event attribution and assessment community are invited to conduct analyses of these events. The goal is to have many different groups assess the same event, using the diverse set of approaches that are used in the study of extreme events.
Register your interest to participate to get future updates
The registration here is intended for groups interested in participating by applying their methodology to a given extreme event. We would like to collect some basic information about your intended approach, and be able to contact you, when appropriate, with information about the events selected for common study.
The attribution component is aimed at (broadly speaking) quantifying the impact of anthropogenic influence on these events. This impact, consistent with event attribution literature, will usually be quantified by estimating forced responses in the probability and intensity of a given event. The assessment component is aimed at estimating the absolute probability / return period of the event in the present-day climate. While many attribution methodologies will estimate this return period along the way, we welcome methodologies that are not explicitly designed for attribution, such as UNSEEN approaches. We encourage groups to contribute to whichever of the components they would like - or both!
The CEAA project will provide basic guidance for the assessment of these events. The guidance is intended to identify the event and provide suggestions on some standards to apply to the different methods so that the results from different approaches are more readily comparable. We recognise that it is not possible to standardise the choice of all relevant datasets, counterfactuals, and outputs, and some groups will need to vary from that. That is entirely acceptable, and an important goal is to make it as easy as possible for different groups to apply their own approaches and participate.
The diversity of approaches is a positive feature of common event attribution and allows for different views and different outcomes for the same event. We hope to learn from these differences (and similarities) to get a better view of what the key uncertainties are, and which outcomes are more robust.
The common event cases are open to all interested participants who provide physically-based assessments of extreme events. This includes quantitative and qualitative approaches, those using models and those not using models, those that are conditional and those that are unconditional, those providing attribution of the event, those providing likelihoods of the event, and those providing process-based understanding of the event. We also welcome contributions on the impacts of these events and on attribution of the impacts.
We are open to suggestions for the selection of events. We want to include some events that are suited to study by a broad range of methods, but we will also include some events that may require the ability to resolve mesoscale processes. The events do not need to be novel, and it is actually helpful if there has already been work to define and assess a given event. The novel element here is provided by the application of a larger set of diverse approaches to the same event.
For each common event assessed, we will try to provide fora for participants to share their results and to develop collective learning from the exercise. This might include dedicated workshops, and CEAA sessions during larger geophysical society meetings. We will also seek to develop collections of peer-reviewed journal articles on the common event cases and learning.